The ability to use a mobile device on any compatible network, irrespective of the original service provider, defines an unlocked phone. This contrasts with a locked phone, which is restricted to a specific carrier’s network. For example, an unlocked Android phone purchased from Verizon can be used with a T-Mobile SIM card, assuming the phone supports the necessary frequencies.
Device freedom offers significant advantages, particularly for frequent travelers who can leverage local SIM cards for potentially cheaper international data and calling rates. Furthermore, an unlocked device generally holds a higher resale value. Historically, carriers locked devices to ensure customer retention, but regulations in many regions have shifted, allowing consumers greater control over their devices.